1. Field of the Invention
The present invention relates to milk-protein hydrolyzate which is bereft of antigenicity of the milk-protein, which activates proliferation of human cutaneous cells, and which is effective for conditioning of hair and skin, and for prevention and recovery from damaged hair and skin. The present invention also relates to hair and skin treating composition such as cosmetic, non-drug and drug products (hereinafter these products shall be referred to as cosmetic and the like) consisting of or containing milk-protein hydrolyzate as the effective component.
2. Discussion of the Background
Heretofore, milk-protein and hydrolyzate thereof have been utilized in cosmetic and the like.
For example, Japanese Unexamined Patent Application Gazette No. 57(1982)-209210 discloses the utilization of amino acids, hydrochlorides of amino acids, alkaline salts of amino acids and peptides, inclusive of peptides originated from milk-protein, as an agent for increasing solubility of bis-(2-pyridylthio-1-oxide)-zinc which is antibacterial agent against dandruff.
Japanese Unexamined Patent Application Gazette published in Japanese language No. 58-500664 (corres. to International Application Gazette No. W082/03008; PCT/AU82/00022) discloses the utilization of polypeptide or protein inclusive of casein as a preventive agent against dental caries.
Japanese Unexamined Patent Application Gazette No. 59(1984)-152317 discloses the utilization of casein, casein hydrolyzate or a mixture thereof as a stabilizer to mutanase solution for preparation of a preventive agent against dental caries.
Japanese Unexamined Patent Application Gazette No. 63(1988)-57515 discloses a bath preparation containing macademian oil and peptide and/or amino acid obtainable by hydrolysis of milk-protein.
Japanese Unexamined patent Application Gazette No. 60(1985)-258102 discloses a hair and skin treating composition containing protein hydrolyzate as a protective agent for hair and skin, wherein the molecular weights of said hydrolyzate are made into 500-5000 for improvement in solubility of the hydrolyzate.
Japanese Unexamined Patent Application Gazette No. 62(1987)-185100 discloses a hair and skin treating composition containing polypeptide as a protective agent for hair and skin, emulsifier or emulsion-stabilizer for the composition, wherein the molecular weights are made into less than 26000 for minimizing stickiness of casein.
Japanese Unexamined Patent Application Gazette No. 64(1989)-11 discloses a method of preparation of a fraction of protein hydrolyzate to be used for an ingredient of cosmetic products, wherein the molecular weights of the hydrolyzate are made to 2000-200000 for eliminating problems of precipitation and/or turbidity in an aqueous solution of the hydrolyzate.
Japanese Unexamined Patent Application Gazette No. 1(1989)-269499 discloses a method of preparation of the peptide originated from casein for use as a hair and skin treating agent, wherein casein is hydrolyzed by trypsin and subtilisin for efficiently yielding peptides having molecular weights in the range of from 300 to 3000 which may improve solubility and chelatability of the peptides, stability of the peptides solution, adsorbability to hairs, affinity to hair and skin, protective property and moisturizing property, however, it does not prove the proliferation activating property of the peptides on human cutaneous cells.
The aims of addition of peptides to hair and skin treating compositions in these references are mainly for hair and skin conditioning effects such as moisturing, adsorbing, film forming and/or protective properties of the hydrolyzate.
In the prior art referred in the above, however, the effectiveness of peptide has not been proved, but merely relies upon rumor or belief. Furthermore there has been a problem that products containing peptide originating from milk protein may sometime cause a problem of allergy.
Some of the inventors of the present application have previously made an invention relating to hydrolyzate of milk-protein and a method of preparation of the same for the purposes of increase in solubility of milk-protein, increase in digestibility of milk-protein, prevention from or treatment of food allergy, treatment of or nutrition to patients having disorders in aromatic amino acids metabolism, and an application for patent for the invention has been filed in Japan by one of the assignees of the present invention (Japanese Patent Application No. 63(1988)-291090; filing date: Nov. 19, 1988 hereinafter this application will be referred to as the prior application.) The inventors of this application have conducted a thorough research with respect to the nature of the hydrolyzate of the prior application, and found that milk protein hydrolyzate having following natures can be used as a hair and skin treating agent or as an ingredient of hair and skin treating compositions: (a) said hydrolyzate is a mixture of peptides having molecular weights less than 1000 daltons; (b) 90% by weight or more of aromatic amino acids included in said mixture is free aromatic amino acids; (c) said mixture has a property to activate proliferation of human cutaneous cells; and (d) said mixture is bereft of antigenicity of the milk protein.
In other words, the inventors of the present invention found that when mi)k protein is hydrolized with two or more enzymes to a certain decomposition rate, the resultant hydrolyzate comprising a mixture of peptides having molecular weights less than 1000 daltons and 90% by weight or more of aromatic amino acids included in said mixture being free amino acids may surprisingly activate proliferation of human cutaneous cells, and is bereft of the antigenicity of the original milk protein, in addition to other properties as a hair and skin treating agent.
It was also found that a specific fraction of milk protein hydrolyzate having following natures can be used as the hair and skin treating agent or as an ingredient of hair and skin treating compositions: (a) said hydrolyzate is a mixture of peptides having molecular weigts less than 1000 daltons; (b) the percentage of aromatic amino acids to the whole amino acids included in the fraction is less than 5% by weight; (c) said mixture activate proliferation of human cutaneous cells; and (d) said mixture is bereft of antigenicity of the milk protein.
In other words, the inventors of the present invention found that peptides having the proliferation activating property on human cutaneous cells are included in a specific fraction of the milk protein hydrolyzate, said fraction being a mixture of peptides having molecular weights less than 1000 daltons, the aromatic amino acids included in said mixture being less than 5% by weight of the whole amino acids included in said mixture, said peptides being bereft of the antigenicity of the original milk protein and having other properties desirable as the hair and skin treating agent.
The present invention is based on these discoveries.